public HE_MeshPoint(Point3d point, HE_Face face)
{
List <HE_Vertex> adj = face.adjacentVertices();
double[] bary = Convert.Point3dToBarycentric(point, adj[0], adj[1], adj[2]);
U = bary[0];
V = bary[1];
W = bary[2];
}
/// <summary>
/// Compute the level on a specified face.
/// </summary>
/// <param name="valueKey">Key of the value to be computed per vertex.</param>
/// <param name="level">Level value to be computed.</param>
/// <param name="face">Face to computee the level in.</param>
/// <param name="line">Resulting level line on the face</param>
/// <returns>True if successful, false if not.</returns>
public static bool GetFaceLevel(string valueKey, double level, HE_Face face, out Line line)
{
List <HE_Vertex> adj = face.adjacentVertices();
List <double> vertexValues = new List <double> {
adj[0].UserValues[valueKey], adj[1].UserValues[valueKey], adj[2].UserValues[valueKey]
};
List <int> above = new List <int>();
List <int> below = new List <int>();
for (int i = 0; i < vertexValues.Count; i++)
{
if (vertexValues[i] < level)
{
below.Add(i);
}
else
{
above.Add(i);
}
}
if (above.Count == 3 || below.Count == 3)
{
// Triangle is above or below level
line = new Line(new Point3d(), new Point3d());
return(false);
}
else
{
// Triangle intersects level
List <Point3d> intersectionPoints = new List <Point3d>();
foreach (int i in above)
{
foreach (int j in below)
{
double diff = vertexValues[i] - vertexValues[j];
double desiredDiff = level - vertexValues[j];
double unitizedDistance = desiredDiff / diff;
Vector3d edgeV = adj[i] - adj[j];
Point3d levelPoint = (Point3d)adj[j] + (edgeV * unitizedDistance);
intersectionPoints.Add(levelPoint);
}
}
line = new Line(intersectionPoints[0], intersectionPoints[1]);
return(true);
}
}
/// <summary>
/// Compute the gradient on a given mesh face given some per-vertex values
/// </summary>
/// <param name="valueKey">Key of the values in the vertex.UserData dictionary</param>
/// <param name="face">Face to compute thee gradient.</param>
/// <returns>A vector representing the gradient on that mesh face</returns>
public static Vector3d ComputeFaceGradient(string valueKey, HE_Face face)
{
List <HE_Vertex> adjacentVertices = face.adjacentVertices();
Point3d i = adjacentVertices[0];
Point3d j = adjacentVertices[1];
Point3d k = adjacentVertices[2];
double gi = adjacentVertices[0].UserValues[valueKey];
double gj = adjacentVertices[1].UserValues[valueKey];
double gk = adjacentVertices[2].UserValues[valueKey];
Vector3d faceNormal = face.Normal / (2 * face.Area);
Vector3d rotatedGradient = (gi * (k - j) + gj * (i - k) + gk * (j - i)) / (2 * face.Area);
Vector3d gradient = rotatedGradient.Cross(faceNormal);
return(gradient);
}
/// <summary>
/// Compute the intersection between a mesh face perimeter and a ray tangent to the face.
/// </summary>
/// <param name="ray">The tangent ray.</param>
/// <param name="Face">The mesh face.</param>
/// <param name="result">The resulting intersection point.</param>
/// <param name="halfEdge">The half-edge on where the intersection lies.</param>
/// <returns></returns>
public static ISRayFacePerimeter RayFacePerimeter(Ray ray, HE_Face Face, out Point3d result, out HE_HalfEdge halfEdge)
{
Vector3d faceNormal = HE_MeshGeometry.FaceNormal(Face);
Vector3d biNormal = Vector3d.CrossProduct(ray.Direction, faceNormal);
Plane perpPlane = new Plane(ray.Origin, ray.Direction, faceNormal, biNormal);
List <HE_Vertex> vertices = Face.adjacentVertices();
Point3d temp = new Point3d();
Line line = new Line(vertices[0], vertices[1]);
if (LinePlane(line, perpPlane, out temp) != ISLinePlane.Point)
{
result = null; halfEdge = null; return(ISRayFacePerimeter.Point);
} // No intersection found
if (temp != ray.Origin && temp != null)
{
result = temp; halfEdge = null; return(ISRayFacePerimeter.Point);
} // Intersection found
line = new Line(vertices[1], vertices[2]);
if (LinePlane(line, perpPlane, out temp) != ISLinePlane.Point)
{
result = null; halfEdge = null; return(ISRayFacePerimeter.NoIntersection);
} // No intersection found
if (temp != ray.Origin && temp != null)
{
result = temp; halfEdge = null; return(ISRayFacePerimeter.Point);
} // Intersection found
line = new Line(vertices[2], vertices[0]);
if (LinePlane(line, perpPlane, out temp) != ISLinePlane.Point)
{
result = null; halfEdge = null; return(ISRayFacePerimeter.NoIntersection);
}
if (temp != ray.Origin && temp != null)
{
result = temp; halfEdge = null; return(ISRayFacePerimeter.Point);
}
else
{
result = null; halfEdge = null; return(ISRayFacePerimeter.Error);
}
}
